Surprised you have not joined our Solt group here.
This morning I started the FACEBOOK GROUP "Genealogy of the Solt families of Pennsylvania (Soldt, Sold, Sult, & Zoll)" in order to;
1)Generate interest in Pennsylvania Solt Genealogy and by link, direct them here to this Solt group to contribute, discuss, and research together. 2)Help promote male Solt's to contribute DNA for genealogical research. 3)Provide links to recorded information
Also you may find this of interest.
I am still looking for this book, but found this excerpt of it "From: Genealogy Quarterly 1998-1904 CBG R. Sol. Genealogy Zoll - Sol 1732-1995. Reinbek, 1997. 134 p., ill., Index. (GZoll). Address of the compiler: Ostlandring 34, D-21465 Reinbek, Germany. The Groningen Sol family has a German origin. Ancestor Johan Christiaan Zoll in 1752 came from the Hessian town Allendorf to the Netherlands, where he joined as a soldier in the Army-State. He lived in various garrison towns around 1764 and settled permanently in the city of Groningen. He had a large posterity, which spread to East Groningen and Drenthe East. In the twenties, some descendants moved to Western Canada. Of recent generations are found in this book also details of family descendants in the female line."
Interesting because Henrich Zoll came from a ship which left Rotterdam, Netherlands with immigrants from the Palinate and he is thought to be Henrich Solt of Pennsylvania!